Power tools, and in particular, power tools used for fastening, may drive a fastener from the tool and into a workpiece in response to power supplied to the fastening tool. Power may be supplied to the fastening tool by, for example, an electrical power source supplying power to the tool through a cord, a compressed air source supplying compressed air to the tool through a hose, a battery supplying stored electrical power to the tool, and the like. Fastening tools driven by electrical power and/or compressed air may operate, essentially, as long as a source of power is available. However, the use of fastening tools driven by electrical power and/or compressed air may, in some circumstances, be cumbersome due to the attachment of the tool to the cord and/or the hose supplying power to the tool, and/or may be limited by the availability of the electrical power and/or compressed air within the range of the tool afforded by the length of the cord and/or the hose. Thus, use of these types of corded tools may also be inconvenient when compared to a cordless tool providing the same capability. For example, use of a battery to supply power to the fastening tool may eliminate the need for a cord or hose attachment of the tool to the power source. However, fastening tools driven by power supplied by a battery may have a relatively limited operating period within the life of the battery, and may be relatively heavy and less nimble. Cordless, combustion powered tools may provide a favorable alternative to corded and/or battery powered tools, due to combination of power, runtime, and lightweight ergonomics.